When expert witnesses offer novel theories on causation, they are at substantial risk of having their testimony excluded.

For example, in Robinson Bowersock v. Davol Inc., No. 17-2068 (7th Cir. Jan. 22, 2019), a hernia mesh personal injury case in which the decedent died one year after her hernia repair, the Court of Appeal upheld a trial judge’s decision to exclude expert testimony on causation.

Unlike prior hernia mesh cases, the mesh did not adhere to the decedent’s bowel or perforate her internal organs. Thus, to establish causation, the plaintiff offered the proposed testimony of Dr. Stephen Ferzoco, a general surgeon with wide hernia mesh experience. Dr. Ferzoco opined that the death was caused by the mesh “buckling” and imperceptibly perforating organs. The trial court excluded this causation testimony, finding it “novel” and unreliable.

The Court of Appeal stated:

The judge properly applied the Rule 702 and Daubert standards in addressing Bard’s motion. He summarized Dr. Ferzoco’s theory that the patch buckled and rubbed against Mrs. Bowersock’s colon, causing fecal matter to escape through an opening that either closed prior to discovery or was not visible to the naked eye. He then explained why this novel theory of causation wasn’t reliable. To begin, the theory wasn’t tested, subjected to peer review, or described in medical literature. See Lapsley, 689 F.3d at 810. Moreover, the phenomena that Dr. Ferzoco described were not found in Mrs. Bowersock’s medical records or autopsy report. Last, the judge discounted Dr. Ferzoco’s contention that he had previously treated patients injured in this manner, explaining that the claim was not substantiated with identified patients or records. See Olinger v. U.S. Golf Ass’n, 52 F.Supp.2d 947, 950 (N.D. Ind. 1999) (“The court cannot evaluate the reliability of the undisclosed methodology or of the principles that support the methodology.”).